It seems to me that it's more complicated than this. When we look at the fossil
record we rarely have genetic information to look at (I believe some TRex soft
tissue was found not too long ago, Otherwise I could have said "never") So we
have to classify species by physical characteristics. When you observe the
great variety of characteristics of say dogs obtained by selective breeders,
one wonders if say a Chihuahua and a great dane would be classified as the same
species if all we had to go on was fossils and had no knowledge of the efforts
of breeders. So significant variation can take place without speciation. But
speciation simply requires a genetic change that results in two populations
that can't interbreed -- and the genetic change does not necessarily mean a
change in external characteristics. So speciation in the fossil record could be
occurring where little or no variation in physical characteristics occurs.

As an engineer I claim no expertise in evolution -- all I know is what I read
in the literature, much of it nontechnical. So of course I am open to
correction.

--- Jim Armstrong <jarmstro@qwest.net> wrote:

> This distinction has always seemed to me exactly as you describe.
> Let microevolution go a long time and you have macroevolution, . . .
> unless you preemptorily define it away.
> However, this minor issue can also be made to go away (sort of) by
> maintaining a young earth position. No long time, no macro-evolution.
> So a working definition for microevolution might default to any
> evolutionary change that occurs within a 6000 (10,000?) year time frame.
> JimA
>
> David Campbell wrote:
>
> > [snip]
> >
> > Secondly, what is microevolution and what is macroevolution? In
> > practice, macroevolution as used by ID or young earth advocates is
> > "evolution I don't believe in" and microevolution is "evolution I
> > accept". Thus, any evolution can be labeled as macro or micro
> > according to the inclination of the individual.
> >
> > [snip]
>
>
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